The class of polymers of carbon monoxide and olefin(s), often referred to as polyketones, has been known for a number of years. Brubaker, U.S. Pat. No. 2,495,286 produced such polymers of relatively low carbon monoxide content in the presence of free radical initiators such as benzoyl peroxide. British Published Patent Specification No. 1,081,304 produced such polymers in the presence of alkylphosphine complexes of palladium salts as catalysts. Nozaki, U.S. Pat. No. 3,694,412, extended the process through the use of arylphosphine complexes of palladium salts and certain inert solvents.
Particularly useful copolymers and terpolymers of carbon monoxide with at least one ethylenically unsaturated compound, e.g., ethylene or ethylene and propylene, have been shown to be linear alternating polymers of the formula --CO(A)-- where A is the moiety obtained by polymerization of the ethylenically unsaturated hydrocarbon through the ethylenic unsaturation. For example, copolymers of carbon monoxide and ethylene are of the formula --CO(CH.sub.2 CH.sub.2)--. The general process for the production of these linear alternating polymers is illustrated by published European Patent Application Nos. 181,014 and 121,965. The process generally involves the use of a catalyst formed from a Group VIII metal compound wherein the metal is palladium, cobalt or nickel, the anion of a non-hydrohalogenic acid having a pKa below 2 and a bidenate ligand of phosphorus, arsenic or antimony. The resulting polymers are generally high molecular weight thermoplastic polymers having utility in the production of structural articles such as containers for food and drink and parts for the automobile industry. The relatively high melting point of the polyketone polymers is of value in many applications, e.g., where a resulting shaped article is to be subjected to conditions of elevated temperature. For other applications, however, high temperature stability is not required and it would be of value to provide plasticized compositions of polyketone polymers with reduced melting temperatures.